Ammonia borane (NH3BH3, AB) is one of promising new hydrogen (H2) storage materials for H2-powered transportation because it contains the highest H2 content of the hydrides (19.6 wt % H2). However, the main obstacle to adopting AB as an on-board H2 carrier is the slow release at the working temperatures of polymer electrolyte membrane fuel cells (80 – 90 oC). We have recently proposed a new way to accelerate H2 release without sacrificing storage density or adding any promoter: CO2 treatment of AB. The CO2-pretreated AB at 4 bars and 85 oC provides rapid H2 release at a level of 8.33 wt% H2 within one hour, while pretreatment with 30 bars CO2 and 100 oC leads to the formation of graphene oxide-boron nanocomposites in a subsequent thermal decomposition up to 700 oC at ambient pressure. Motivated by these promising results, the central theme of this project is to understand the reaction mechanisms of enhanced hydrogen release of CO2-treated AB and CO2 reduction to the graphene oxide composite using AB. Through this understanding, we aim at achieving usable H2 storage capacity higher than 10 wt% (to meet 2017 DOE target) and maximizing the yield of GO-boron nanocomposites. We are trying to use various reduction agents to convert CO2 to carbon materials for electrochemical energy storage applications.

■ Dynamic Adhesion Behaviors in Clathrate Hydrate Systems: The main goal of this proposal is to understand the dynamic adhesion interactions between clathrate hydrates and various oil-water interfaces. Elucidating the adhesion behaviors of hydrate particles in multi-phase systems consisting of gas, oil, water, and solid surfaces may provide fundamental insights into the avoidance of hydrate plugs in gas/oil delivery lines and processing units. To understand the adhesion behavior subject to the phase transition and fluid motion, the mechanism for capillary bridge formation and aggregation between hydrate particles, partially converted water droplets, and water droplets should be identified in a micro-scale domain. Then, this micro-scale adhesion mechanism can be interpreted to understand the macro-scale adhesion behaviors. We will quantify the changes in dynamic adhesion when accompanying surface-active agent (surfactants and nano-particles) injection, substrate (e.g. metal surfaces in the pipelines) aging and various surface properties of roughness, hydrophobicity, and hydrophilicity.

■ Design of energy cascaded systems for heat and pressure pinches: The intensification of reaction and separation can lead to the simplification of a complex process, dramatic economic savings, and environmentally benign operation. The main task in realizing this technology is to achieve a solid understanding of the interaction between multiple reactions and separation in one physical shell or in a fewest number of operation units. We will use the visualization tools with mathematical models.

Recruiting: For anyone who is interested in the research above, please contact me (Jae Woo Lee, jaewlee@kaist.ac.kr, x3940) or visit the EFDL lab (x3980).